Pipe armor



Oct. 13, 1936. c.-o. WILLENBERG P IPE ARMOR Filed July 6, 1955 Patented Oct. 13, 1936 UNITED STATES PATENT OFFICE PIPE ARMQR. Carl 0. Willenberg, Long Beach, Calif. Application July 1935, Serial No. 30,101

Claims. (01. 138-64) This invention is a means and a method for the manufacture thereof, for the protection of earth-buried conduits.

Buried iron pipe used in the transportation of 5 fluids such as oils and gases are subject to rapid deterioration because of corrosive agents in the soil and this is aggravated if the pipes are subject to much heat and to temperature variations. I

Oils are usually kept up to a temperature of about 150 F. and may vary in a range of 30 a day in a line of pipe. This is only an example, as conditions vary greatly with different oils.

It is well known that buried pipes in this industry are coated with a corrosive resistant such I as bitumen, and it has been heretofore proposed to protect this coat from chemical and mechanical attack by soil forces. 7

An object of the present invention is to provide effectively against the destructive agents by a means which is characterized in its simplicity of apparatus and mode of production, and of the manner of application to a pipe.

The status of the art, as set forth in the Mo- Gary Patent No. 1,871,125 for instance, is advanced by the present invention wherein the coating is protected from both chemical and ,mechanical soil attack and, further, the heat of the flowing fluid is protected against loss by the device of this invention.

The invention resides primarily in a shell of pre-molded, matching, composition sections free from any back-bone or fabric foundation, and including a non-emulsified, bituminous magma including insulative, stiffening and toughening inert materials of mineral character, and the said sections designed to provide for longitudinal change of pipe length by heat effect with a minimum of chafing in the coating of the pipe. The invention consists in certain advancements in this art as set forth in the ensuing disclosure and having, with the above,additional objects and advantages as hereinafter developed, and whose construction, combinations and details of means, and the manner of operation will be made manifest in the description of the herewith illustrative embodiment; it being understood that modifications, variations and adaptations may be resorted to within the scope, principle, and spirit of the invention as it is more directly claimed hereinbelow.

Figure 1 is a sectional side elevation of the applied shell.

Figure 2 is a cross section of the applied shell.

Oil field pipes are currently butt welded with a resultant ridge 3 at the joint of the lengths 2 of the pipe and the pipe is coated all over externally with a protective layer 4 of bitumen to reduce as far as possible corrosive action of the soil in which the pipe is buried.

Unless the coating is protected it is cut and 5 scarred by mechanical soil action and the present invention includes a shell of longitudinally extending sections 5 to protect the coat. Due to changes of temperature of the fluid flowing in the pipe this makes it necessary to provide a 10 shell which will compensate for expansion and contraction longitudinally of the pipe without chafing the coat.

Therefore, the shell is made of sections 5 which are capable of being interbonded or cemented 15 with the coat 4 by a homogeneous tie. That is, the coat and the shell are of a similar base, in this case bitumen, and their zones of contact are, therefore, of like physical properties and. may be connected in an integral joint.

The sections 5 are best applied when they are formed, ready for application by pre-molding to desired size and shape. In the present case they are formed with uniform-arc internal and external corrugations of ridges 6 and valleys 1 free from corners or angles, and the thickness of the material being substantially uniform.

The ends of the sections are rebated at 8 to provide for reception of the butt weld 3 to avoid this forming an obstacle lifting the section from 30 the coat 4.

The sections 5 are preferably semicylindrical in cross-section and their longitudinal edges are morticed and tenonned at 9 to effect a tight joint and are riveted at It]. 35

The sections 5 are composed of non-emulsified bitumen in which is thoroughly mixed with ground asbestos and diatomaceous earth as inert fillers to such a degree as to produce a stiff and tough and waterproof shell element; all com- 40 pressed during molding.

All meeting surfaces of the sections both together and with the pipe coat 4 may be fused to weld them or they may be united by a suitable bitulithic cement. 45

It will be seen that the transverse corrugations of the applied shell sections will by inherent fiexure of their bends provide for longitudinal variation of pipe length'as to the armor 5 due to changes of temperature without disrupting 50 the homogeneous tie joining the armor sections to the coating and that chafing of the latter will be eliminated. It is understood that there is norelative slipping between the pipe 2 and its closely adhering coat 4, but the earth- 55 c the coating 4; this latter being non-slipping on the pipe 2. Since there is no relative movement as between the armor joints of union with the pipe coating 4 because of the accordion action of the corrugated armor there will be no surface,

chafing or scumng of the pipe coating.

The shell sections are thus so joined to' the pipe coating that a hermetic seal is effected at numerous quite close lines around the coat with a high degree in efliciency in' the exclusion or corrosive agents from the pipe and having a high protective value against mechanical attrition on the coating; which protection is facilitated by the accordion action of the corrugated shell'or armor.

The composition of the shell may be varied,

but an example is twenty parts diatomaceous earth, ten parts asbestos and seventy parts bitumen, by volume of mix.

What is claimed is: 1. Means for theheat insulation, and earth stress protection and corrosion prevention of bitulithic coated, metallic conduits of the fluid transportation class: comprising a shell made of compressed, pre-molded, stifi sections said sections comprised of bituminous magma free of any skeleton or core body and including inert minerals which stiffen and toughen the magma and provide a heat insulating quality to the shell, the saidsections being peripherally internally and externally corrugated to compensate for longitudinal variations in length of conduit, from incidental and natural causes, to which the shell is affected, to avoid chafing of the coat.

2. A pipe armor section of pre-molded, compressed, rstifiened bitumen which is internally and externally corrugated transversely from end to end and whose wall thickness is substantially uniform along the section; the corrugations being evenly pitched to respond uniformly under changes in the length of pipe to which the armor is affixed.

; I ,3. A bituminous armor, for application to a pipe coated with bitumen, and which presents transverse corrugations having internal spaced zones for contact and homogeneous juncture with the coat of the pipe; said armor capable of longitudinal variation with similar variation of the pipe to which it may be applied whereby to avoid chafing the coat, and consisting of compressed, pre-molded sections formed of mixed bitumen, asbestos and diatomaceous earth. r 4. The combination with a-buried pipe havin a coat of a bituminous nature, of an armor comprising compressed, pre-molded sections which are transversely corrugatedand are of a bituminous composition, and have homogeneous bonds at-spaced intervals along thepipe for coeval length variation therewith without chaiing the coat.

5."I'he combination with a coated pipe, of aprotective armor therefor consisting of a shell characterized by transverse corrugations which afiord an accordion action to compensate for longitudinal expansion and contraction of the pipe and eliminate chafing of the'coat at points of contact with the armor.

CARL O. WILLENBERG. 

